Floor scrubbing brush

ABSTRACT

A BRUSH FOR USE IN ROTARY TYPE FLOOR SCRUBBING MACHING COMPRISING A FLAT BACKBOARD HAVING BRISTLES IMPREGNATED WITH AN ABRASIVE MATERIAL ATTACHED TO THE BACKBOARD AND EXTENDING THEREFROM AT RANDOM LENGTHS WITH THE MAJORITY VARYING IN THE RANGE OF 10 PERCENT TO 25 PERCENT FROM THE MEDIAN LENGTH.

p 20, 1971 R. M. BARRY 3,605,347

FLOOR SCRUBBING BRUSH I Filed March 27. 1970 FIE; z

ml i /%/////////////%///////////l/ w W 5 KW 3x; g

' INVISN'I ()k ROBERT M 84KB) FI 3 I I 4 rraknwys United States Patent Ofice Patented Sept. 20, 1971 3,605,347 FLOOR SCRUBBING BRUSH Robert M. Barry, St. Paul, Minn'., assignor to Multi-Clean Products Incorporated, St. Paul, Minn.

Filed Mar. 27, 1970, Ser. No. 23,318 Int. Cl. B24b 23/02 US. Cl. 51-330 4 Claims ABSTRACT OF THE DISCLOSURE A brush for use in a rotary type floor scrubbing machine comprising a flat backboard having bristles impregnated with an abrasive material attached to the backboard and extending therefrom at randomlengths with the majority varying in the range of percent to 25 percent from the median length.

BACKGROUND OF THE INVENTION In rotary type floor scrubbing machines a flat brush is rotated about a vertical axis as the machine is moved over the floor surface. The brush has a flat horizontally disposed backboard with bristles extending downwardly therefrom. In conventional construction of the brush the backboard is provided with downwardly opening pockets spaced uniformly over its under side. Strands of the bristle material are bunched and stapled medially into each of said pockets so that each end of'the strand serves as a separate bristle. Where the strands in each bunch are of equal length those at the bottom of the bunch or closest to the staple will obviously project slightly farther from the backboard than those near the top and thus form longer bristles. It is accordingly the general practice to trim the bristles to an equal length after they have been attached to the board.

In recent advancements in the manufacture of brushes of this type it has been found desirable to impregnate or coat the bristles with an abrasive grit to increase the scrubbing action thereof. This material renders the bristle extremely difiicult to trim and yet it must be applied to the bristle before it is inserted into the backboard.

SUMMARY OF THE INVENTION It is found that bristles coated with abrasive material perform more effectively when the bristles in certain proportions of the overall total have varying lengths within certain prescribed limits.

It is accordingly the object of this invention to provide a floor scrubbing brush which need not be trimmed after assembly and yet which provides improved scrubbing efficiency over conventional rotary brush construction.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a side elevation of a rotary floor scrubbing machine with the brush in scrubbing engagement with the floor surface.

FIG. 2 is an enlarged fragmentary vertical section through the brush showing the manner of attaching the bristles to the backboard of the brush.

FIG. 3 is a side elevation of a portion of the brush constructed in accordance with the present invention with the brush bristle in scrubbing engagement with the floor surface.

,FIG. 4 is a greatly enlarged side view of one of the shorter and one of the longer bristles coated with abrasive material in scrubbing contact with the floor surface.

DETAILED DESCRIPTION Referring now more particularly to the drawing, reference characters will be used to denote like parts or structural features in the different views. A rotary floor scrubbing machine is denoted generally by the number 10 and comprises a base formed by a brush 11 mounted for rotation within a circular shield 12 and having powered connection with a motor mounted on the shield and disposed within housing 14. A handle 15 is connected to the motor housing 14 for moving the base over the floor surface S.

The brush 11 comprises a flat backboard 1-6 having a plurality of downwardly opening pockets 17 (FIG. 2) spaced over the underside thereof and a bunch of bristles 18 secured as by a staple 19 in each pocket. The bristles are formed of strands of material of uniform length. However, as shown in enlarged detail in FIG. 2, they will project varying distances downwardly from the backboard 16. Bristles next to the staple 19 will extend downwardly substantially farther than those held against the upper closed end of the socket 17 and those bristles in between will extend downwardly intermediate distances.

In FIG. 2, the line A denotes the median length of all of the bristles 18. Line B denotes the length of the shortest and line C the length of the longest bristles each varying approximately 25 percent from the median length of all of the bristles. The random length of the bristles is an important feature of this invention and it is found that most effective cleaning action is obtained where at least a majority of the bristles are 10 percent to 25 percent shorter or longer than the median length of all of the bristles. It is also possible to achieve this same result by using random length bristles.

The bristles are preferably formed of nylon strands coated with an abrasive material containing particles of grit '20 (FIG. 4). Accordingly, with the random length of the bristles a substantial portion of the grit embedded in the longer bristles will come into engagement with the floor surface S giving the brush an improved scrubbing action over a trimmed brush having bristles of uniform length.

The brush is also found to be more effective than a trimmed brush in scrubbing irregular floor surfaces as the random length bristles are brought into more intimate contact with clips and rises in the surface.

Another advantage in the brush lies in its ease of manufacture as the trimming process is eliminated saving both labor and machinery. It is found that the grit in abrasive impregnated bristles rapidly wears down trimming tooling.

The brush construction accordingly economically and effectively carries out the objectives hereinabove set forth.

Having now therefore fully illustrated and described my invention, what I claim to be new and desire to protect by United States Letters Patent is,

I claim:

1. A brush for a floor scrubbing machine comprising a flat rigid horizontal backing member, a plurality of bristles attached to said backing member and extending downwardly therefrom, said bristles being impregnated along their sides with an abrasive material and extending in varying lengths from the backing member whereby when said brush is applied to a floor surface the shorter bristles will engage said surface endwise while the longer bristles will be flexed into sidewise engagement therewith to bring the abrasive material into contact with the surface.

2. The subject matter of claim 1 wherein the majority of the bristles are shorter or longer than the median length of all of the bristles.

3. The subject matter of claim 1 wherein the majority of the bristles are 10 percent to 25 percent shorter or longer than the median length of all of the bristles.

4. The subject matter of claim 1 wherein said bristles are formed of strands of nylon material of equal length stapled medially in bunches to the underside of thebacking member so that the higher strands within each bunch 8/1964 Nielsen 15180 3/1970 Coneway 15180X 10 DONALD G. KELLY, Primary Examiner US. Cl, X.R. 

